This invention relates generally to electrical machinery condition assessment analyzers and more particularly, to methods and analyzer systems for assessing partial discharge (PD) in machinery.
Partial discharge events in an insulation system are a pulse release of energy that propagates out from its site of origin. The propagation occurs according to the structure surrounding the partial discharge event. An internally generated partial discharge pulse propagates and appears at the end regions, such as a high or low voltage bushing, as specific pulse waves in accordance with the structure, the location of the origin of the pulse, and the pulse characteristic itself. Although partial discharge analysis has been used for many years on various electrical equipment, noise recognition/cancellation and data interpretation remain difficult. It is important to separate noise from true partial discharge data. It is also important to be able to identify and locate partial discharge activity sources. At least some known analyzer systems use a time of flight approach towards noise cancellation. Other known analyzer systems use a more basic, less efficient gating approach. However, such approaches are deficient in removing noise from partial discharge signals and do not allow for differing partial discharge response based on differing operating and environmental conditions ambient to the machine and/or insulation system.